Improving error message for typos on kool run

cmd/parser/parser.go

@@ -2,13 +2,31 @@ package parser
 
 import (
 	"errors"
-	"kool-dev/kool/cmd/builder"
+	"fmt"
 	"os"
 	"path"
 	"sort"
 	"strings"
+
+	"kool-dev/kool/cmd/builder"
 )
 
+// ErrPossibleTypo implements error interface and can be used
+// to determine specific situations of not-found scripts but
+// where similar names exist, indicating a possible typo
+type ErrPossibleTypo struct {
+	similars []string
+}
+
+// Error formats a default string with the similar names found
+func (e *ErrPossibleTypo) Error() string {
+	if len(e.similars) == 1 {
+		return fmt.Sprintf("did you mean '%s'?", e.similars[0])
+	}
+
+	return fmt.Sprintf("did you mean one of ['%s']?", strings.Join(e.similars, "', '"))
+}
+
 // Parser defines the functions required for handling kool.yml files.
 type Parser interface {
 	AddLookupPath(string) error
@@ -67,6 +85,7 @@ func (p *DefaultParser) Parse(script string) (commands []builder.Command, err er
 		parsedFile      *KoolYaml
 		found           bool
 		previouslyFound bool
+		similarScripts  []string
 	)
 
 	if len(p.targetFiles) == 0 {
@@ -92,8 +111,18 @@ func (p *DefaultParser) Parse(script string) (commands []builder.Command, err er
 				// in another file! let's warn about that
 				err = ErrMultipleDefinedScript
 			}
+		} else {
+			// we could not find the intented script so let's check for a typo
+			if foundSimilar, similars := parsedFile.GetSimilars(script); foundSimilar {
+				similarScripts = append(similarScripts, similars...)
+			}
 		}
 	}
+
+	if err == nil && len(commands) == 0 && similarScripts != nil && len(similarScripts) > 0 {
+		err = &ErrPossibleTypo{similarScripts}
+	}
+
 	return
 }
 

cmd/parser/parser_test.go

@@ -4,9 +4,24 @@ import (
 	"kool-dev/kool/cmd/builder"
 	"os"
 	"path"
+	"strings"
 	"testing"
 )
 
+func TestErrPossibleTypo(t *testing.T) {
+	err := &ErrPossibleTypo{[]string{"script1"}}
+
+	if !strings.Contains(err.Error(), "script1") {
+		t.Errorf("unexpected error message: %s", err.Error())
+	}
+
+	err = &ErrPossibleTypo{[]string{"script1", "script2"}}
+
+	if !strings.Contains(err.Error(), "script1") || !strings.Contains(err.Error(), "script2") {
+		t.Errorf("unexpected error message [2]: %s", err.Error())
+	}
+}
+
 func TestDefaultParser(t *testing.T) {
 	var p Parser = NewParser()
 
@@ -67,6 +82,12 @@ func TestParserParse(t *testing.T) {
 		t.Error("failed to parse testing kool.yml")
 	}
 
+	if _, err = p.Parse("testin"); err == nil {
+		t.Error("unexpected non-error on typo")
+	} else if _, foundSimilar := err.(*ErrPossibleTypo); !foundSimilar {
+		t.Errorf("unexpected error; should be ErrPossibleTypo; got %s", err)
+	}
+
 	if commands, err = p.Parse("invalid"); err != nil {
 		t.Errorf("unexpected error; error: %s", err)
 	}

cmd/parser/yml.go

@@ -6,9 +6,14 @@ import (
 	"kool-dev/kool/cmd/builder"
 	"os"
 
+	"github.com/agnivade/levenshtein"
 	"gopkg.in/yaml.v2"
 )
 
+// SimilarThreshold represents the minimal Levenshteindistance of two
+// script names for them to be considered similarss
+const SimilarThreshold int = 2
+
 type yamlMarshalFnType func(interface{}) ([]byte, error)
 
 // KoolYaml holds the structure for parsing the custom commands file
@@ -70,6 +75,18 @@ func (y *KoolYaml) HasScript(script string) (has bool) {
 	return
 }
 
+// GetSimilars checks for scripts with similar name.
+func (y *KoolYaml) GetSimilars(script string) (has bool, similars []string) {
+	var name string
+	for name = range y.Scripts {
+		if levenshtein.ComputeDistance(name, script) < SimilarThreshold {
+			has = true
+			similars = append(similars, name)
+		}
+	}
+	return
+}
+
 // ParseCommands parsed the given script from kool.yml file onto a list
 // of commands parsed.
 func (y *KoolYaml) ParseCommands(script string) (commands []builder.Command, err error) {

cmd/parser/yml_test.go

@@ -51,6 +51,10 @@ func TestParseKoolYaml(t *testing.T) {
 		return
 	}
 
+	if hasSimilars, similars := parsed.GetSimilars("single-lne"); !hasSimilars || len(similars) != 1 {
+		t.Errorf("unexpected return on GetSimilars %v - %v", hasSimilars, similars)
+	}
+
 	if cmds, err = parsed.ParseCommands("single-line"); err != nil {
 		t.Errorf("failed to parse proper single-line; error: %s", err)
 		return

cmd/run.go

@@ -49,22 +49,20 @@ func NewKoolRun() *KoolRun {
 // Execute runs the run logic with incoming arguments.
 func (r *KoolRun) Execute(originalArgs []string) (err error) {
 	var (
-		script string
-		args   []string
+		script string   = originalArgs[0]
+		args   []string = originalArgs[1:]
 	)
 
 	// look for kool.yml on current working directory
 	_ = r.parser.AddLookupPath(r.envStorage.Get("PWD"))
 	// look for kool.yml on kool folder within user home directory
 	_ = r.parser.AddLookupPath(path.Join(r.envStorage.Get("HOME"), "kool"))
 
-	script = originalArgs[0]
-	args = originalArgs[1:]
-
 	if r.commands, err = r.parser.Parse(script); err != nil {
 		if parser.IsMultipleDefinedScriptError(err) {
 			// we should just warn the user about multiple finds for the script
 			r.Warning("Attention: the script was found in more than one kool.yml file")
+			err = nil
 		} else {
 			return
 		}

go.mod

@@ -4,6 +4,7 @@ go 1.14
 
 require (
 	github.com/AlecAivazis/survey/v2 v2.1.1
+	github.com/agnivade/levenshtein v1.1.0
 	github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6 // indirect
 	github.com/blang/semver v3.5.1+incompatible
 	github.com/creack/pty v1.1.11

go.sum

@@ -47,10 +47,13 @@ github.com/PuerkitoBio/purell v1.1.1 h1:WEQqlqaGbrPkxLJWfBwQmfEAE1Z7ONdDLqrN38tN
 github.com/PuerkitoBio/purell v1.1.1/go.mod h1:c11w/QuzBsJSee3cPx9rAFu61PvFxuPbtSwDGJws/X0=
 github.com/PuerkitoBio/urlesc v0.0.0-20170810143723-de5bf2ad4578 h1:d+Bc7a5rLufV/sSk/8dngufqelfh6jnri85riMAaF/M=
 github.com/PuerkitoBio/urlesc v0.0.0-20170810143723-de5bf2ad4578/go.mod h1:uGdkoq3SwY9Y+13GIhn11/XLaGBb4BfwItxLd5jeuXE=
+github.com/agnivade/levenshtein v1.1.0 h1:n6qGwyHG61v3ABce1rPVZklEYRT8NFpCMrpZdBUbYGM=
+github.com/agnivade/levenshtein v1.1.0/go.mod h1:veldBMzWxcCG2ZvUTKD2kJNRdCk5hVbJomOvKkmgYbo=
 github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/alecthomas/units v0.0.0-20190717042225-c3de453c63f4/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
+github.com/arbovm/levenshtein v0.0.0-20160628152529-48b4e1c0c4d0/go.mod h1:t2tdKJDJF9BV14lnkjHmOQgcvEKgtqs5a1N3LNdJhGE=
 github.com/armon/circbuf v0.0.0-20150827004946-bbbad097214e/go.mod h1:3U/XgcO3hCbHZ8TKRvWD2dDTCfh9M9ya+I9JpbB7O8o=
 github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6/go.mod h1:grANhF5doyWs3UAsr3K4I6qtAmlQcZDesFNEHPZAzj8=
 github.com/armon/go-metrics v0.0.0-20180917152333-f0300d1749da/go.mod h1:Q73ZrmVTwzkszR9V5SSuryQ31EELlFMUz1kKyl939pY=
@@ -95,6 +98,7 @@ github.com/daviddengcn/go-colortext v0.0.0-20160507010035-511bcaf42ccd h1:uVsMph
 github.com/daviddengcn/go-colortext v0.0.0-20160507010035-511bcaf42ccd/go.mod h1:dv4zxwHi5C/8AeI+4gX4dCWOIvNi7I6JCSX0HvlKPgE=
 github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
 github.com/dgryski/go-sip13 v0.0.0-20181026042036-e10d5fee7954/go.mod h1:vAd38F8PWV+bWy6jNmig1y/TA+kYO4g3RSRF0IAv0no=
+github.com/dgryski/trifles v0.0.0-20200323201526-dd97f9abfb48/go.mod h1:if7Fbed8SFyPtHLHbg49SI7NAdJiC5WIA09pe59rfAA=
 github.com/docker/distribution v2.7.1+incompatible h1:a5mlkVzth6W5A4fOsS3D2EO5BUmsJpcB+cRlLU7cSug=
 github.com/docker/distribution v2.7.1+incompatible/go.mod h1:J2gT2udsDAN96Uj4KfcMRqY0/ypR+oyYUYmja8H+y+w=
 github.com/docker/spdystream v0.0.0-20160310174837-449fdfce4d96 h1:cenwrSVm+Z7QLSV/BsnenAOcDXdX4cMv4wP0B/5QbPg=